Rash of West Nile virus cases hits Butte County

OROVILLE -- Four people have been hospitalized recently with West Nile virus, the Butte County Public Health Department reported Wednesday.

At least two were still in the hospital Wednesday, said Dr. Mark Lundberg, the county's health officer.

The rash of cases shows high numbers of mosquitoes all over the county are carrying the virus, said Matt Ball, manager of the Butte County Mosquito and Vector Control District.

"We've got risk out there, and people need to protect themselves," Lundberg said.

The best protection, health officials say, is avoiding being outside at dawn and dusk, when mosquitoes are most active. If you have to be out then, wear long pants and long-sleeved shirts and use an effective mosquito repellent.

It's also important to get rid of standing water on your property, in flower-pot saucers, bird baths and other containers, Ball said.

The virus is transmitted when mosquitoes feed on infected birds and then pass the infection on by biting people.

The four cases the department reported Wednesday bring the county's total number of human West Nile cases to five so far this season. All five victims were hospitalized.

All but one case was classified as "neuroinvasive," the worst type of infection, Lundberg said. In these cases, the virus causes a brain infection.

If the infection is bad enough, much of the brain is affected and systems of the body, including breathing, can shut down, Lundberg said. That's why some people die of West Nile.

The first Butte County case this year was earlier this month. A woman in her 60s in south Chico was stricken.

In the latest cases, people in their 40s and 50s have become ill. They live in Oroville, Biggs and off Highway 70 south of Oroville. It's believed the person who got sick in the latest case is from Gridley.

Ball said district workers have been busy eliminating mosquito breeding areas, spraying adult mosquitoes and preventing larva from developing into adults.

He said this is the peak time of year for mosquitoes.

Ball and Lundberg both said they thought people have gotten complacent about trying to prevent mosquito bites.

The number of West Nile cases dropped in the last few years. Ball said it's distressing to see the virus making a comeback this year all over the country.

He said it's estimated for every person who gets neuroinvasive West Nile, 150 get the milder form, which may cause flu-like symptoms and sometimes no symptoms at all.

According to the national Centers for Disease Control, as of Tuesday, 48 states had reported West Nile virus infections in people, birds or mosquitoes.

A total of 1,590 cases of West Nile virus disease in people, including 66 deaths, had been reported to the CDC. That is the highest number of cases reported through the last week in August since West Nile virus was first detected in the United States in 1999.

Staff writer Larry Mitchell can be reached at 896-7759, lmitchell@chicoer.com, or followed on Twitter @LarryMitchell7.